Studies on the oxygen-linked binding of chloride and phosphate will be continued. We have obtained evidence that Val-1 alpha is a major binding site for the chloride anion and that Val-1 (beta) does not bind chloride in an oxygen-linked manner. We had postulated that Lys-82 (beta) was a second major binding site for chloride. In the coming year we will test this hypothesis by doing similar experiments with Hb Providence which has an asparagine residue instead of a lysine residue at position 82 of the beta-chain. Studies on the anti-sickling properties of glyceraldehyde will be extended to test for other aldehydes that may have a similar effect. Experiments on the effects of glyceraldehyde on the physiological properties of the red cell in vitro will be tested. The site of binding and the nature of the linkage of glyceraldehyde to hemoglobin will also be examined.